Erythropoietic Protoporphyria (EPP): Causes, Signs, Symptoms, Investigations, Treatment
Erythropoietic Protoporphyria (EPP) is a rare inherited porphyria in which there is accumulation of a specific porphyrin, protoporphyrin, due to excessive production from the bone marrow. The cause of this is deficiency of the enzyme ferrochelatase, which leads to accumulation of Protoporphyrin in the red blood cells, liver and the skin resulting in skin sensitivity to sunlight. EPP commonly starts in childhood. It affects both men and women equally.
There is no cure for Erythropoietic Protoporphyria (EPP). Treatment aims at managing the symptoms so that the patient can live a normal life as much as possible.
Causes of Erythropoietic Protoporphyria (EPP)
The cause is deficiency of a converting enzyme, ferrochelatase, the function of which is to bind the iron to protoporphyrin in order to produce hemoglobin. The shortage of this enzyme leads to increased levels of protoporphyrin in the blood. When the blood circulates in the skin, the protoporphyrin absorbs the full force of the sunlight leading to generation of a chemical reaction, which can damage the surrounding tissues. This causes burning pain or itching type of sensation. If the blood vessels are involved, then there can be a slight leakage of blood resulting in swelling of the skin.
Signs and Symptoms of Erythropoietic Protoporphyria (EPP)
Symptoms vary from patient to patient in severity and commonly consist of:
- Patient experiences tingling, burning, itching sensation of the skin upon sun exposure.
- There may also be redness and swelling present after a few minutes of skin exposure to direct sunlight.
- In the days which follow, the skin becomes more sensitive to temperature extremes and even to indirect light, such as light which is reflected off snow, water, sand, glass etc.
- Infants start screaming or crying after being in the sunlight.
- Older children complain of burning pain.
- Repeated exposure to the sun causes skin thickening on the knuckles and scars on the nose, cheeks, and back of the hands.
- Very rarely, a minor percentage of patients may develop liver problems or damage with this condition.
Investigations for Erythropoietic Protoporphyria (EPP)
- A blood test confirms the diagnosis by measuring the level of protoporphyrin in the blood.
- A stool sample can also be taken to measure the amount of protoporphyrin.
- Urine tests can be done only to exclude other types of porphyria.
- The hemoglobin level is also measured as patients suffering from EPP also suffer from mild anemia.
- The patient may be monitored for liver problems by yearly blood tests and ultrasound of the liver.
Treatment for Erythropoietic Protoporphyria (EPP)
As of now, there is no known cure for Erythropoietic Protoporphyria Treatment is done to manage this condition better by giving the skin protection from the sunlight, so it can tolerate it better.
Medications Given in Erythropoietic Protoporphyria (EPP) Include:
- Beta-carotene capsules are helpful in this condition and are safe to use; however, they can give the skin a mild orange tinge and cause some stomach upset.
- Antihistamines are beneficial for those patients who have swelling, as a result of this condition.
- Phototherapy consisting of narrow-band UVB and PUVA therapy comprises of limited exposure to artificial UV light and is given about thrice a week for around five weeks. This will cause slight skin thickening and give the patient a tan, which acts as a natural sunscreen and helps the patient better tolerate the sun exposure.
- Treatments comprising the use of MSH (melanotan), L-acetyl cysteine and dihydroxyacetone paint are under research.
- Patients should avoid unnecessary sun exposure and always wear special sunscreens and protective clothing, such as wide brimmed hats, long sleeves etc.